order are saprotrophic, as suggested by several
authors (Kreisel 1969 ; Sunhede 1989 ). Most
trufflelike fungi are believed to form ectomy-
corrhizae; Sclerogaster is an exception. One
species ofGeastrum,G. fimbriatum, has been
described as forming ectomycorrhizae with
Fagus(Agerer and Beenken 1998 ), but their
observation indicated the absence of a Hartig
net. The ecological roles of Geastrales species
warrant further investigation.
Systematics: most taxa in Geastrales have
been treated in the order Lycoperdales, along
with puffballs (Lycoperdon) (Fischer 1900 ;
Miller and Miller 1988 ; Zeller 1949 ), but early
molecular studies (Hibbett et al.1997a) demon-
strated thatGeastrumandLycoperdon, both of
which possess a powdery gleba at maturity, are
only distantly related. Kreisel ( 1969 ) first
segregated Geastrales from Lycoperdales but
did not provide a Latin diagnosis. In addition,
Kreisel ( 1969 ) included only two genera,Geas-
trumand Myriostoma, in the order. Hosaka
et al. ( 2006 ) formally described Geastrales
with a broader concept, including several pre-
viously unrecognized taxa in the order.
Geastrales, which as a whole is moderately
supported as monophyletic, is divided into four
families—Geastraceae, Sclerogastraceae, Sche-
nellaceae, and Sphaerobolaceae—that are all
strongly supported as clades (Hosaka and
Castellano 2008 ; Hosaka et al. 2006 ). Geastra-
ceae, Sclerogastraceae, and Schenellaceae form
a clade, with an ambiguous relationship among
families (Hosaka and Castellano 2008 ). Within
Geastraceae,Myriostoma, the only taxon pos-
sessing multiple stomata, represents the earliest
branch, suggesting that the evolutionary trend
is reduction from multiple stomata to a single
stoma. The early-diverging taxa within the
order, Sphaerobolaceae and Schenellaceae,
form basidiospores in peridioles, and this may
be the ancestral character state.
A total of 7 genera and 64 species are cur-
rently recorded in the order (Kirk et al. 2008 ),
but a number of undescribed species have been
discovered for Geastrum and Sclerogaster
(Hosaka and Castellano 2008 ; Kasuya et al.
2012 ). Furthermore, Kasuya et al. ( 2012 )
demonstrated that Geastrum triplex, which
was recorded from all continents except
Antarctica, should be separated into multiple
species. Therefore, a significantly higher
number of species may be recognized in the
future.- Phallales
Overview: this order is famous for its
stinkhorns (Phallaceae) and lattice stinkhorns
(Clathraceae) (Fig.14.4a), but recent molecular
phylogenetic studies have shown that a number
of sequestrate taxa are also included. Most taxa
in the Phallales have fruiting bodies with a
gelatinous layer and a gelatinous to mucilagi-
nous gleba. Fruiting bodies of epigeous stink-
horns are often brightly colored (white and
yellow to bright red) and composed of a pseu-
doparenchymatous receptacle with multiple
arms (Fig.14.4a). The fruiting bodies of most
sequestrate taxa contain thick gelatinous layers,
and their gleba remains gelatinous to mucilagi-
nous. However,GastrosporiumandCalvarula
have a powdery gleba at maturity (Domı ́nguez
de Toledo and Castellano 1997 ). Spores of most
taxa are small, ellipsoid, smooth, and without
ornamentation, but a few taxa, such asKjeldse-
niaandGastrosporium, have warty spore sur-
faces (Colgan et al. 1995 ; Domı ́nguez de Toledo
and Castellano 1997 ).
Ecological diversity: most taxa are thought
to be saprotrophic due to their lignicolous
habit, but at least one species (Protubera canes-
cens) has been reported to be ECM (Malajczuk
1988 ). This report, however, is suspect because
P. canescenshas recently been confirmed as an
immature form ofIleodictyon(May et al. 2010 ).
It is likely that all members of the order are
saprotrophic, but further investigation is nec-
essary.
Phallales represents one of the prime exam-
ples of interactions of Fungi with arthropods
(Nouhra and Domı ́nguez de Toledo 1994 ). The
fruiting bodies of epigeous stinkhorns possess a
gleba that becomes slimy and malodorous at
maturity. The odor of a mature gleba attracts
a variety of mycophagous arthropods, espe-
cially flies, that disperse the basidiospores
(Tuno 1998 ). Unlike spores of many sequestrate
fungi, those of Phallales (including sequestrate392 D.S. Hibbett et al.